Administration of the MapR-DB is done primarily via the command line (maprcli) or with the MapR Control System (MCS). Regardless of whether the MapR-DB table is used for binary files or JSON documents, the same types of commands are used with slightly different parameter options. MapR-DB administration is associated with tables, columns and column families, and table regions.

The MapR Data Access Gateway is a service that acts as a proxy and gateway for translating requests between lightweight client applications and the MapR cluster. This section describes considerations when upgrading the service, how to modify configuration settings, and how to administer and manage the service.

These maprcli commands are used to create and manage Change Data Capture (CDC) changelogs. A changelog is used to establish a relationship between a MapR-DB source table (JSON or binary) and a MapR-ES stream topic and to manage the propagation process.

Resumes replication between a sourceMapR-DB binary or JSON table and a replica of that table. Replication can be paused during autosetup and replication phases. When replication resumes, it continues from where it left off.

Note: The mapr user is not treated as a superuser. MapR-DB does not allow the mapr user to
run this command unless that user is given the relevant permission or permissions with
access-control expressions

Parameters

path

The path to the source table that you want to replicate.

For a path on the local cluster, start the path at the volume mount
point. For example, for a table named testsrc under a
volume with a mount point at /volume1, specify the following path:
/volume1/testsrc

For a path on another cluster, you must also specify the cluster name
in the path. For example, for a table named
customersrc under volume1 in the
sanfrancisco cluster, specify the following
path:/mapr/sanfrancisco/volume1/customersrc

replica

The path to the replica.

For a table on the local cluster, start the path at the volume mount
point. For example, for a table named testdst under a
volume with a mount point at /volume1, specify the
following path: /volume1/testdst

For a table on another cluster, you must also specify the cluster
name in the path. For example, for a table named customerdst
undervolume1 in the
sanfrancisco cluster, specify the following path:
/mapr/sanfrancisco/volume1/customerdst

Note: For replication to a table, the command will fail if the replica path
you specify points to table that already exists.

columns

By default, all columns in the source table are replicated.

If you do not want to replicate all columns in the table, you can
specify specific columns to replicate:

For binary tables

Provide a comma-separated list of column families or columns from a
certain column family (column family:qualifier). For example, use the
following syntax to replicate the column family purchases and the column
stars in the reviews column family: -columns
purchases,reviews:stars

Note: While the column families that you specify must already exist in the
source table, the columns that you specify do not have to exist in the
destination table for replication to succeed. If the column is added at a
later date, replication for that column will start at that time.

For JSON tables

Provide a comma-delimited list of fields to replicate. Include the full
field path for each field.

Example

Suppose your table
contains documents that contain this general
structure:

{
"_id" : "ID",
"a" :
{
"b" :
{
"c" : "value",
},
"e" : "value"
}
}

To
replicate fields a, c, and
e, you would specify these field
paths:

a,a.b.c,a.e

Do not use quotation marks
and do not include spaces after commas.

Suppose now that
a.b and a.e were custom column
families. You want to replicate only the default column family and column
family a.e. To do so, you would specify field paths like
this:

",a.e"

The empty string before the comma
indicates the default column family.

synchronous

A Boolean value that specifies whether replication is synchronous or
asynchronous. The values are true or
false. Asynchronous (false) is the
default.

multimaster

A Boolean value that specifies whether or not to set up a multi-master
topology. The values are true or false.
Basic master-slave topology (false) is the default.

throttle

A Boolean value that specifies whether or not to throttle replication
operations. Throttle the replication stream to minimize the impact of the
replication process on incoming operations during periods of heavy load. The
values are true or false. No throttle (false) is the
default.

networkencryption

A Boolean value that specifies whether or not to enable on-wire
encryption. The values are true or false.
No encryption (false) is the default. If
you set this to true, the local cluster and any other
cluster that is part of the replication process must be enabled for
security.

networkcompression

The type of on-wire compression.

The types are:

off

on (default)

lzf

lz4

zlib

lz4 is the default compression which it set by parameter values onorlz4.

directcopy

A Boolean value that specifies whether or not autosetup will use the
directcopy option . The values are true or
false. Autosetup with direct copy
(true) is the default. If you set this parameter to
false, the cluster will run autosetup without the
directcopy option. For more information, see Replica Autosetup for MapR-DB Tables.

Note: If a table was originally created in MapR 5.x and the
maprcli table replica autosetup command is specified
with directcopy=false, then an error, “Copy Table failed
for tables”, occurs. This is due to the introduction of new table meta
information in 6.0. It is recommended that replication be setup using
directcopy=true (which is the default). If the
default method is not desired, then replication should be setup
manually.

useexistingreplica

When the directcopy parameter is set to true (default),
this Boolean value specifies whether or not an existing table can be used as
the replica table. The values for this parameter are true
or false. No reuse of existing tables
(false) is the default. If a table exists with the
specified name, and this parameter is set to false, the create table
operation will fail.